Troubleshooting M1010 fuel-fired heater?

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The M1010 box heater is PN 10530B. I found the TM for the 10560G, TM 9-2540-205-24&p. I worked through the troubleshooting section to the point where I'm supposed to remove the igniter. But my 10530B doesn't match the TM's 10560G pictures, so I'm hoping someone can point me to the right TM, or provide guidance.

I removed the cover. I have fuel coming out the bleeder screw. I have 24VDC at several terminals on the heater. I have air blowing out the vent inside the cab. When I put my hand above the heater, I feel heat coming from what I presume to be the ignition circuitry. But the control panel indicator light never comes on, and the air blowing into the cab never gets hot. I saw no evidence of fuel leaking out, so I don't think my problem is flooding. I left it in "start" mode for about 5 minutes before I gave up.

I include a photo and video below. At the end of the video, I turn off the light. You can see that nothing is glowing on the heater. The sound in the video is all the heater. The engine is off.

https://youtu.be/jGLX7Zun2zY

The -20 manual says how to replace the heater. The -34 manual says how to disassemble and reassemble, but not how to troubleshoot...

Any guidance or pointers to troubleshooting documentation would be appreciated.

Thanks!

 

[Recovry4x4]

While I can offer no assistance with the heater, I would like to share this. There was a guy at the GA Rally last year that had an M887. He removed his heater and installed a window shaker a/c in its place. It's low on the list but something I want to do. Guess my point is if you find yourself needing parts, I may be able to help.

 

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The fan blows air, I get fuel out the bleeder, but no heat. I pulled the glow plug, a coil which looks like an old-school car cigarette lighter on the end of a long spring. I closed the fuel valve, turned on the heater, and the coil immediately glowed hot. I get no diesel smell, so it seems no diesel is getting near that hot glow plug, even though I get diesel out of the bleeder.

I've found wasp nests made of mud in odd corners of the truck, so I thought perhaps something had built a nest inside. I started disassembly, and I thought I'd put up pictures of what I have so far. Perhaps someone familiar with these units will see something of interest. It all looks OK to my untrained eye. The fan spins freely, the wiring looks intact, etc.



My current theory is that fuel is not making it into the combustion chamber, perhaps due to a blockage, or perhaps the valve isn't opening. If anyone has suggestions as to how best to proceed, I'd appreciate any insights. I've never worked with one of these before.

 

[njjeeper]

Are you getting 24v DC to the the solenoids? You should be able to hear them click as well when in the start position. They wont have voltage in the RUN position until the unit fires and the light comes on. My guess from your description is that they arent getting energized. Either a problem with one of the safety circuits or wiring....

 

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Are you getting 24v DC to the the solenoids? You should be able to hear them click as well when in the start position. They wont have voltage in the RUN position until the unit fires and the light comes on. My guess from your description is that they arent getting energized. Either a problem with one of the safety circuits or wiring....

That's likely. I'm trying to trace through the wiring to figure this out. Is there a way to manually work the valve, and see if it moves freely? I'd love to see documentation about how to effectively troubleshoot these.

 

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I took the valve body apart. The cork washers behind the coils gave me pause, but the rest of the disassembly was straightforward. I was afraid I'd destroy the cork washers in removing them, but with patience and some dental tools I got them loose and out with no damage. First photo shows the 3 screws that hold the coil housing in place, visible once you remove the cork washer. Other photos show valve seats. I cleaned this up and reassembled. Fuel flow calibration tomorrow.



I removed the igniter tube and confirmed that the wick is present and in good shape. It was completely dry, confirming that my valve was the problem. Fingers crossed!

 

[rosco]

I have worked on these things over the decades -- they can be touchy, and I by no means understand them. While they are all basically on the same principal, there are numerous models. Their failures have been for numerous reasons - never the same. Sometimes something just sticks & no worky. Your suspicion about the igniter, might be close. Also, I have done like you, not found a thing, put it back together and it works. There is still a chance. What I have found: The flat thing in the very 1st photo, lowest left, "over heat switch", check for continuity. The old ones used to have a wick of something/braided stainless steel. That sometimes burned out. The two solenoids; I always thought they worked backwards. Very tiny holes - they have to be on high, to start, so if it was dry, that might be it. Clean the filters! Yes, you should be able to feel each click. But then you have to get fuel (is the supply pipe turned on, w/fuel pump running & pumping? If you keep tinkering with it, you'll learn to understand it. Then if you get a couple of spares for parts, you can swap stuff. Be cautious about getting it flooded & getting it lit. That brings to mind, my most gratifying fix, but also most spectacular. I was in my M211 w/m105 trailer for gear & camp, on the Sagavanirtuk River - North Slope. It was an honest -40, and the engine heater wouldn't start. But it should have as it was checked out. I was running out of tricks, and afraid of running the batteries down. I was surmising the temp was too cold on the fuel/gasoline. (at those temperatures, gasoline ignites about like cold #2 diesel) I about lost my hearing when I gave it a shot of either, but it started/ran, and the engine started.

Good Luck

 

[njjeeper]

I have a few of these types of units and while some are grumpy about starting and one likes to smoke before it starts, they all work. The dry wick pretty much proves you don't have power at the solenoids or you don't have fuel pressure to push fuel through them. I don't like taking these units completely apart as some of the gaskets and such are hard to replace and if they don't seal you can have all kinds of problems with fire and fumes. Check the basics, fuel pressure and energized solenoid valves and move on from there. The overheat switch is fairly durable but a quick continuity test will tell you if its working.

 

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Thanks guys. I had fuel out the bleeder and power where it was supposed to be before I tore this apart. I've learned a lot in the process, mostly from SS. Bjorn's been a big help, and his article answered a *lot* of questions.

 

[cranetruck]

I have worked on these things over the decades -- they can be touchy, and I by no means understand them. While they are all basically on the same principal, there are numerous models. Their failures have been for numerous reasons - never the same. Sometimes something just sticks & no worky. Your suspicion about the igniter, might be close. Also, I have done like you, not found a thing, put it back together and it works. There is still a chance. What I have found: The flat thing in the very 1st photo, lowest left, "over heat switch", check for continuity. The old ones used to have a wick of something/braided stainless steel. That sometimes burned out. The two solenoids; I always thought they worked backwards. Very tiny holes - they have to be on high, to start, so if it was dry, that might be it. Clean the filters! Yes, you should be able to feel each click. But then you have to get fuel (is the supply pipe turned on, w/fuel pump running & pumping? If you keep tinkering with it, you'll learn to understand it. Then if you get a couple of spares for parts, you can swap stuff. Be cautious about getting it flooded & getting it lit. That brings to mind, my most gratifying fix, but also most spectacular. I was in my M211 w/m105 trailer for gear & camp, on the Sagavanirtuk River - North Slope. It was an honest -40, and the engine heater wouldn't start. But it should have as it was checked out. I was running out of tricks, and afraid of running the batteries down. I was surmising the temp was too cold on the fuel/gasoline. (at those temperatures, gasoline ignites about like cold #2 diesel) I about lost my hearing when I gave it a shot of either, but it started/ran, and the engine started.

Good Luck

One small correction, the "HI" is locked out during the start sequence. It is hardwired into the control box.

 

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Update: I went to calibrate the valve. The good news is I get fuel coming through the valve now. The bad news is the valve also leaks fuel in several places. Since the valve sits above the igniter, I don't think I want a leaky valve dripping fuel down the side of the heater, into a puddle below the heater, and into the igniter. I'm no expert on this stuff, but that sounds like a bad idea... So now I get to go disassemble it further, and make gaskets for the parts that leak.

I did contact the manufacturer, sort of. The company was bought a few times, and the name changed a few times. I did find the business that currently owns the company that used to make these heaters. They have limited parts available. They do have manuals, for $125!

We still have a manual for this heater, we sell them for $125.00. We still have few parts left for this heater, but not many.

Regards,
Lisa Dauby
Contract Administrator
Meggitt (Troy), Inc.
3 Industrial Drive, Troy, IN 47588 US
Tel: 812-547-7071 ext. 2121
lisa.dauby@meggitt.com
www.meggitt.com

 

[Csm Davis]

Update: I went to calibrate the valve. The good news is I get fuel coming through the valve now. The bad news is the valve also leaks fuel in several places. Since the valve sits above the igniter, I don't think I want a leaky valve dripping fuel down the side of the heater, into a puddle below the heater, and into the igniter. I'm no expert on this stuff, but that sounds like a bad idea... So now I get to go disassemble it further, and make gaskets for the parts that leak.

I did contact the manufacturer, sort of. The company was bought a few times, and the name changed a few times. I did find the business that currently owns the company that used to make these heaters. They have limited parts available. They do have manuals, for $125!

That's nuts! $125! For a heater manual that is crazy.

 

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That's nuts! $125! For a heater manual that is crazy.

I think they're still calibrated for selling to the Military.

 

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I tore the fuel valve completely apart, cleaned everything, reassembled, and calibrated it. It's supposed to output 14 ml/min in low/start mode, and 28 ml/min in high. I set the low to 15 ml/min, but my high is only 20 ml/min. I figure the start mode is more important to have to spec, since starting is a problem for me anyway. I can probably live with less than the full 30,000 BTUs in my 52 sq ft box.

I now get steady white smoke out the exhaust when I start, but it never lights and I get no heat. I let it run for several minutes in start mode, and all I get is a steady stream of smoke. Next step, I'll tear apart the front end and see whether my wick is getting wet.

I do have 12V to the igniter, which does get hot. I did see a wick when I disassembled before, though I have not seen it since I fixed the fuel valve. I have 24V to the Start solenoid, and nothing to the "high" solenoid. The fan runs. All is as it should be, except I get smoke instead of heat.

For the record, disassembly requires what we used to call ignition wrenches (small wrenches), a valve stem removal tool (there's a valve stem under the adjustment screw) and some sort of tool to allow you to reach in and pull out the filter screen behind the fuel input fitting.

I still have a slow drip from the valve. I'll need to disassemble it yet again, once I determine the source of the leak.I may need to use RTV to replace some old O rings, if I can't find replacements.